The invention relates to a vehicle comprising an internal combustion engine and vehicle electrical system, which comprises a battery, a current distributor, a starter, a generator and electrical loads.
The electrical system of a motor vehicle supplies to a multiplicity of electrical components. The electrical power is provided by a battery of the vehicle electrical system and/or by a generator. In modern vehicles, an increasing number of electrical loads is implemented as high current loads. This makes special requirements on the stability of the voltage in the vehicle electrical system since high current consumption reduces the voltage output by the battery and/or the generator. In particular the starter as a high current load with peak values up to more than 600 A is more frequently used in modern vehicles comprising an automatic engine-start-stop function than in a conventional vehicle.
The high current consumption of the starter results in measures described in the prior art for supporting the voltage in the vehicle electrical system, which compensate the voltage dip in the vehicle electrical system. This relates, for example, to the integration of a series resistor for limiting the starter current according to EP 2 469 070 A1, or to the parallel connection of additional voltage sources such as super capacitors according to EP 1 564 862 A1.
It is an object of the invention to describe an improved vehicle comprising an internal combustion engine and comprising a vehicle electrical system, which comprises a battery, a current distributor, a starter, a generator and electrical loads.
This object is achieved by a vehicle according to the independent claims. Advantageous embodiments and refinements of the invention arise from the dependent claims.
According to the invention, the vehicle comprises a first supply line which connects the current distributor to a starter terminal, and the vehicle comprises a second supply line which connects the current distributor to a support point, wherein the electrical loads and the generator are electrically connected to the support point
Accordingly, there are two supply lines in the vehicle for distributing the electrical potential of the battery to the components in the vehicle electrical system. The starter is connected to one of the lines, and the generator and the electrical loads are connected to the other one of the two lines. Through this, a voltage-stabilizing vehicle electrical system architecture is provided.
According to a preferred embodiment of the invention, the vehicle comprises a switch that is located between the support point and the starter terminal, and a control unit that controls the switch. The switch is configured as a break contact.
Thus, in a default setting of the switch position, the switch connects the support point and the starter terminal to one another. The support point can be provided with load circuits for electrical loads of the vehicle, which load circuits are connected via fuses.
Furthermore, it is advantageous if the vehicle comprises at least one control device, if a status signal for requesting a start can be transmitted at least unidirectionally to the control device via a data connection, and if the control device sends a control signal for opening the switch to the control unit upon a start request.
The control device and the control unit thus are participants in a data transmission system of the vehicle. For example, in the case of a vehicle comprising an automatic engine-start-stop function, a status signal for requesting a start can be transmitted to the control device during an engine stop by actuating a clutch pedal.
According to a preferred variant of the invention, the control unit opens the switch prior to a start of the engine and closes the switch after a start of the engine.
In particular during the start and at the time of maximum current consumption of the starter, the support point and the starter terminal are separated with regard to their potential level. The start current flowing during an engine start for electrically supplying the starter thus flows through the supply line connecting the starter terminal separately from the supply line connecting the support point and therefore does not reduce the potential at the support point.
Another advantage is obtained if the data transmission system is configured as a LIN bus and if the control unit is configured as a LIN module comprising a processor and a driver. A LIN bus is a cost-effective and robust data transmission system.
Furthermore, the support point can be utilized as a jump start support point for external power supply to the vehicle.
The invention is based on the considerations set out below. The vehicle electrical system of a motor vehicle usually comprises a battery, a high-current fuse distribution box, a generator, a starter for an internal combustion engine and lines for connecting these components, as well as terminals for further electrical loads.
In particular when integrating an automatic engine-star-stop function, different measures for avoiding undervoltages at loads, for example control devices, are implemented in this vehicle electrical system architecture. This can involve connecting an additionally integrated battery for stabilization of the vehicle electrical system. The disadvantage of such a stabilization measure is that it constitutes a cost-intensive and installation-space-consuming solution and requires an operating strategy for the additional energy storage and the switch unit.
Proposed is a vehicle electrical system architecture which, in contrast, exhibits less complexity and higher robustness. The electrical potential is provided in the DC voltage vehicle electrical system via two separate electrically parallel lines. In particular the starter is supplied through a separate starter line. As a result, the voltage dropping at the starter line does not affect the parallel second line.
In addition, a switching element is integrated in the vehicle electrical system through which the potential at the starter can be connected to the potential at a load support point at which the generator is also interconnected. Thus, the electric resistance is halved and the battery can be charged with less electrical power loss. The switching element is switched using a module, preferably a LIN module, which is integrated in the vehicle bus system.
A preferred exemplary embodiment of the invention is described below with reference to the attached drawing. Further details, preferred embodiments and refinements of the invention become apparent therefrom. In particular and schematically,
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.